Tension let off device for a knitting machine

ABSTRACT

The device pertains to a knitting machine for knitting a plurality of narrow elastic tapes using elastic yarn. It comprises a rectangular supporting frame on vertical legs so that the frame straddles a plurality of rows of roving cans or bins. A pair of vertically contiguous rollers are mounted on the frame extending across each row of cans. The rollers in each pair are provided with meshing gears at one end so that they rotate in opposite directions. The lower roller of each pair is connected by a sprocket chain with the lower roller of the adjacent pair so that a single drive will drive all the rollers. A single upper roller at the front of the frame forms the drive for the other rollers. The knitted tapes leave the knitting machine at the bottom under tension and pass around a driven roller which is driven from the knitting machine drive. This roller is connected by a sprocket chain to a lower roller at the front of the frame which it drives at the same speed. The lower roller is connected by a sprocket chain to the front upper roller with a reduced gear drive which cuts the speed of the upper roller to half the speed of the lower roller. All the frame rollers, driven from the front upper roller operate at this reduced speed. The knitted tape passes around the lower front roller and up to the upper front roller. Then around this and through the pairs of rollers on the frame. Tension on the tapes is reduced by half at the upper front roller due to the reduced speed. As each tape reaches a predetermined roving can, it is directed downwardly from the rollers, releasing the remaining tension. Each tape passes through one or more pairs of rollers on the frame until its can is reached.

United States Patent Adler [451 Feb. 26, 1974 TENSION LET OFF DEVICE FORA KNITTlNG MACHINE [75] Inventor: Edwin I. Adler, Providence, RI.

[73] Assignee: Atlas Braid Company, Cumberland,

[22] Filed: May 24, 1972 [2]] Appl. No.: 256,430

[52] US. Cl. 66/152, 139/304 [51 1 ink-2213.11.11: 29 4b l [58] Field ofSearch ..66/152, 149 R; 139/291 R, 139/291 C, 304, 307; 28/1 CS; 19/159R 56] M References Cited UNITED STATES PATENTS 2,771,098 11/1956 Ross139/307 1,392,939 10/1921 Hathaway 139/291 R 3,110,432 11/1963 Smith226/189 3,515,174 6/1970 Herkenberg 139/291 R 2,598,738 6/1952 Wilkie19/159 R 3,522,715 8/1970 Merritt et al 66/149 R Primary Examiner-W. C.Reynolds Assistant Examiner-A. M. Falik Attorney, Agent, or FirmMaxSchwartz [5 7] ABSTRACT The device pertains to a knitting machine forknitting a plurality of narrow elastic tapes using elastic yarn. 1t

comprises a rectangular supporting frame on vertical legs so that theframe straddles a plurality of rows of roving cans or bins. A pair ofvertically contiguous rollers are mounted on the frame extending acrosseach row of cans. The rollers in each pair are provided with meshinggears at one end so that they rotate in opposite directions. The lowerroller of each pair is connected by a sprocket chain with the lowerroller of the adjacent pair so that a single drive will drive all therollers. A single upper roller at the front of the frame forms the drivefor the other rollers. The knitted tapes leave the knitting machine atthe bottom under tension and pass around a driven roller which is drivenfrom the knitting machine drive. This roller is connected by a sprocketchain to a lower roller at the front of the frame which it drives at thesame speed. The lower roller is connected by a sprocket chain to thefront upper roller with a reduced gear drive which cuts the speed of theupper roller to half the speed of the lower roller. All the framerollers, driven from the front upper roller operate at this reducedspeed. The knitted tape passes around the lower front roller and up tothe upper front roller. Then around this and through the pairs ofrollers on the frame. Tension on the tapes is reduced by half at theupper front roller due to the reduced speed. As each tape reaches apredetermined roving can, it is directed downwardly from the rollers,releasing the remaining tension. Each tape passes through one or morepairs of rollers on the frame until its can is reached.

8 Claims, 6 Drawing Figures PATENTED 3, 793 .852

sum 2 or a v 'FIG.3

TENSION LET OFF DEVICE FOR A KNITTING MACHINE BACKGROUND OF THEINVENTION When elastic yarn is knitted into a narrow elastic tape, amodern high speed knitting machine is used which can knit approximately40 tapes simultaneously. For efficient operation of such a knittingmachine, it is essential that the yarn be maintained under a suitabletension at all times. The elastic yarn is therefore fed to the machineunder tension, using a yarn frame with a suitable tensioning device foreach spool of yarn. When the tape is finished, the tension is released.However, applicant has found that the released tension has a tendency toback into the knitting machine even though the tapes are drawn from themachine by a driven polished steel roller. The tapes will slip on thepolished steel roll to some extent to relax the tension in the knittingmachine. Since this relaxation of the tension is not uniform, the smoothand efficient operation of the knitting machine is upset, causing brokenends, stoppages, etc.

SUMMARY OF THE INVENTION The present invention provides a let off devicewhich maintains the tension on the finished tape to the final point ofrelease into its receiving can or bin. This maintains the tension in theknitting machine at the let off end. The device passes the finishedtapes around a series of driven rolls which first reduce the tensionapproximately by half. Then the tapes are passed between pairs ofpinching rolls which positively hold each tape under tension. Each tapepasses from a pair of pinching rolls to a roving can or otherreceptacle, releasing the tension. The device is simple, a supportingframe straddles a plurality of rows of roving cans. The frame supports apair of pinching rolls extending across each row of cans. The tapes passfrom the knitting machine to a lower and then to an upper roller at thefront of the frame. The lower roller is driven from the knitting machineroller. The upper roller is driven from the lower roller but the speedis cut in two. The pinching rollers are driven from the upper roller atthe reduced speed. The tapes pass from the upper roller, at half thetension, through the pinching rollers and into their respective rovingcans or bins. Thus the let off tension at the knitting machine isconstantly maintained, the relaxed tension at each can being confined tothe exit from between the pinching rollers.

DESCRIPTION OF DRAWINGS.

FIG. 1 is a side elevation of a let off device embodying my presentinvention;

FIG. 2 is a top plan view thereof, partially broken away;

FIG. 3 is a front elevation thereof;

FIG. 4 is a side elevation of the drive take-off from the knittingmachine;

FIG. 5 is a side elevation of one of the yarn tensioning elements; and

FIG. 6 is a top plan view of one of the yarn tensioning devices.

DESCRIPTION OF THE INVENTION.

Referring more in detail to the drawings, FIGS. 1, 2 and 3 illustratethe device of the present invention. A rectangular frame is formed ofangle iron or other suitable material, comprising side bars 10, a frontbar 11 and a rear bar 12. The frame is supported on vertical legs 13 ateach comer. In the illustrated form, it is assumed that the knittingmachine is making 40 elastic tapes, and the device is provided with 40roving cans 14 positioned beneath the frame in 4 rows of 10 to a row,each can 14 receiving one of the tapes.

Tension on the tapes is maintained by passing the tapes around andbetween a series of driven rollers so that the let off of the tension ispostponed until the very last moment. Referring to FIG. 4, the back ofthe knitting machine 15 is provided at its base l6 with a gear 17 whichis driven counterclockwise by the sprocket chain 18 from the knittingmachine drive (not shown). Mounted on the base 16, in front of the gear17, is a roller having a gear 19 at one end which meshes with the gear17 to drive the roller counterclockwise. The tapes 20 leave the knittingmachine under tension and pass around and under the roller driven at thespeed of exit of the tapes. From this point the tapes 20 pass under theplatform 21 at the front of the machine 15, see FIG. 1, and into thedevice of the present invention.

Positioned on the floor in front of the device is an elongated strip 22having a plurality of vertical spaced guide pins 23, the tapes 20passing between the guide pins 23. Mounted at the lower front portion ofthe device is a shaft 24 having a roller 25 adjacent the center, thetapes 20 passing from the guide pins 23 down and around the roller 25and then upwardly. Just below the upper surface of the frame, a roller26 is mounted above the roller 25, but extending across the entire frontof the frame, see FIG. 3.

The drive of the rollers 25 and 26 is shown in FIGS. 1, 3 and 4. Theshaft 24 carrying the roller 25 is driven through a sprocket chain 27from the roller gear 19. All gear sizes being equal, the roller 25 isrotating at the same surface speed as the roller at the back of themachine 15 so that the tapes 20 maintain their tension up to and aroundthe roller 25, and to the roller 26. Now viewing FIGS. 1 and 3, one endof the shaft 24 is provided with-agear 28 which meshes with a gear 29mounted on the vertical leg 13 directly above it. The

gear 29 has a small gear 30 which drives a sprocket chain 31. The chain31 passes around a gear 32 mounted at the end of the roller 26 shaft.Note that the gear 32 is twice the diameter of the gear 30 to reduce therotation of the roller 26 to one half the speed of the roller 25. Thetapes 20 thus leave the roller 26 at half the tension.

Now viewing FIGS. 1, 2 and 3, a lower driven roller is journalled in theside bars 10 above each row of cans 14, at 33. On top of the side bars10, above each point 33, is a bearing 34 with a U-shaped open slot. Anupper roller 35 is provided with a shaft 36 which enters'each slotloosely, so that the upper shafts 36 will allow the rollers 35 to reston the lower rollers which are journalled and supported at 33.

One end of the roller 26 shaft is provided with a gear 37 which drives achain 38 which drives the nearest lower shaft 33, see FIGS. 1 and 2. Nowthis shaft 33 drives the adjacent one through a chain drive 39, whichdrives the next one through the chain 40, and finally the last onethrough the chain 41.

Now as can be seen in FIGS. 2 and 3, the tapes 20 pass around the upperfront roller 26 through a plurality of distributing guide pins 42. Agroup of pins 42 are mounted on the front cross bar 11 in front of eachrow of cans 14. With 4 cans in a row, 4 tapes 20 enter each group ofpins 42. Now as can be seen in FIG. 2, the 4 tapes all pass between thefirst set of rollers and one of the tapes is then directed down into thenearest can 14 with its tension released. The other 3 tapes now passthrough the next set of rollers and another tape enters the next can.The last 2 tapes now pass through the next rollers with one tapedropping, leaving the last tape for the last set of rollers and the lastcan. This is repeated at each group of pins for each row of cans.

While I have illustrated the use of roving cans 14, any suitable bin orcontainer can be used. For example, a container on wheels can be usedfor easier removal of a full container and quick replacement with anempty one. The device thus post-pones the release of the tension on eachtape until the moment of release into the receiving container.Furthermore, each tape is being held between pinching rollers so thatthe released tension does not work back into the knitting machine.

While any suitable tensioning means can be used for feeding the yarn tothe knitting machine, I have found that best results are obtained withthe type shown in FIGS. 4, and 6. The yarn frame 43 is provided with ahorizontal bar 44 in front of each spool of yarn 45. A strip of metal 46is mounted on the bar 44 with its inner end, adjacent the spool, bent upat 47. The strip is mounted on the bar 44 by an elongated screw 48 onwhich a ceramic cylinder 49 is loosely positioned. At the outer end ofthe strip 46, an elongated screw 50 provides a support for a similarceramic cylinder 51. Opposed plates 52 are loosely mounted on thecylinder 51 and a plurality of washers 53 are mounted over the plates52.

A short distance along the bar 44, in a direction toward the knittingmachine, another elongated screw 54 is provided with a loose ceramiccylinder 55 and a plate and washer arrangement 56 such as the plates andwashers 52 and 53. The yarn 57 passes through an eyelet 58 in thevertical portion 47, see FIG. 6. The yarn 57 now passes around thecylinder 49, across and around the cylinder 55 between the plates 56,back to the cylinder 51 between the plates 52, then back to the knittingmachine. The various turns made by the yarn, plus the pressure betweenthe plates, causes a frictional drag to create a tension on the yarn.This tension can be controlled and varied by changing the number ofwashers at 53 and 56 which exert the pressure on the plates and theyarn.

The device of the present invention is therefore simple in constructionand easy and economical to manufacture and assemble. The knittingmachine runs rapidly and smoothly with a uniform yarn tension both atentry and let off. Other advantages of the present invention will bereadily apparent to a person skilled in the art.

I claim:

1. A tension let off for a knitting machine for knitting a plurality ofnarrow elastic tapes under tension, comprising a rectangular frame, avertical leg at each corner of said frame supporting said frame inraised position, a plurality of open top containers beneath said framein aligned rows, one container for each tape issuing under tension fromthe knitting machine, means for passing the tapes under tension from theknitting machine to said frame, means on said frame for reducing thetension on the tapes, and means on said frame for distributing the tapesto their respective containers and for releasing the tension on thetapes, said means being driven from the knitting machine drive.

2. A tension let off device as in claim 1, wherein said passing meanscomprises a driven roller at the lower rear of the knitting machine anda roller at the lower front of said frame, drive means from said machineroller to said frame roller, said tapes passing under tension aroundsaid machine roller and to and around said frame roller, and saidtension reducing means includes a roller mounted at the upper front ofsaid frame, said upper roller being driven from said lower frame rollerat half the speed thereof, said tapes passing from around said lowerframe roller upwardly and over the said upper roller to reduce thetension by half.

3. A tension let off device as in claim 1, wherein said distributingmeans includes a pair of vertically contiguous rollers mountedtransversely in said frame above each row of containers, the lower ofeach of said rollers being driven, each tape passing under tensionbetween at least one pair of rollers then down into the respectivecontainer to release the tension.

4. A tension let off device as in claim 1, wherein said means are drivenby gear and sprocket chains from the knitting machine to the tapepassing means, then from the tape passing means to said reducing means,and finally from said tension reducing means to said distributing means.

5. A tension let off device as in claim 2, wherein said distributingmeans includes a pair of vertically contiguous rollers mountedtransversely in said frame above each row of containers, the lower ofeach of said rollers being driven, each tape passing under tensionbetween at least one pair of rollers then down into the respectivecontainer to release the tension.

6. A tension let off device as in claim 2, wherein said means are drivenby gear and sprocket chains from the knitting machine to the tapepassing means, then from the tape passing means to said reducing means,and finally from said tension reducing means to said distributing means.

7. A tension let off device as in claim 3, wherein said means are drivenby gear and sprocket chains from the knitting machine to the tapepassing means, then from the tape passing means to said reducing means,and finally from said tension reducing means to said distributing means.

8. A tension let off device as in claim 5, wherein said means are drivenby gear and sprocket chains from the knitting machine to the tapepassing means, then from the tape passing means to said reducing means,and f1- nally from said tension reducing means to said distributingmeans.

1. A tension let off for a knitting machine for knitting a plurality ofnarrow elastic tapes under tension, comprising a rectangular frame, avertical leg aT each corner of said frame supporting said frame inraised position, a plurality of open top containers beneath said framein aligned rows, one container for each tape issuing under tension fromthe knitting machine, means for passing the tapes under tension from theknitting machine to said frame, means on said frame for reducing thetension on the tapes, and means on said frame for distributing the tapesto their respective containers and for releasing the tension on thetapes, said means being driven from the knitting machine drive.
 2. Atension let off device as in claim 1, wherein said passing meanscomprises a driven roller at the lower rear of the knitting machine anda roller at the lower front of said frame, drive means from said machineroller to said frame roller, said tapes passing under tension aroundsaid machine roller and to and around said frame roller, and saidtension reducing means includes a roller mounted at the upper front ofsaid frame, said upper roller being driven from said lower frame rollerat half the speed thereof, said tapes passing from around said lowerframe roller upwardly and over the said upper roller to reduce thetension by half.
 3. A tension let off device as in claim 1, wherein saiddistributing means includes a pair of vertically contiguous rollersmounted transversely in said frame above each row of containers, thelower of each of said rollers being driven, each tape passing undertension between at least one pair of rollers then down into therespective container to release the tension.
 4. A tension let off deviceas in claim 1, wherein said means are driven by gear and sprocket chainsfrom the knitting machine to the tape passing means, then from the tapepassing means to said reducing means, and finally from said tensionreducing means to said distributing means.
 5. A tension let off deviceas in claim 2, wherein said distributing means includes a pair ofvertically contiguous rollers mounted transversely in said frame aboveeach row of containers, the lower of each of said rollers being driven,each tape passing under tension between at least one pair of rollersthen down into the respective container to release the tension.
 6. Atension let off device as in claim 2, wherein said means are driven bygear and sprocket chains from the knitting machine to the tape passingmeans, then from the tape passing means to said reducing means, andfinally from said tension reducing means to said distributing means. 7.A tension let off device as in claim 3, wherein said means are driven bygear and sprocket chains from the knitting machine to the tape passingmeans, then from the tape passing means to said reducing means, andfinally from said tension reducing means to said distributing means. 8.A tension let off device as in claim 5, wherein said means are driven bygear and sprocket chains from the knitting machine to the tape passingmeans, then from the tape passing means to said reducing means, andfinally from said tension reducing means to said distributing means.